1. Field of the Invention
The present invention relates to mother substrates, substrate elements, and methods for manufacturing the same. In particular, the present invention relates to a mother substrate used for manufacturing individual substrate elements including electronic device elements such as resonators and filters.
2. Description of the Related Art
Known technologies related to the present invention are disclosed in, for example, Japanese Unexamined Patent Application Publication Nos. 8-293752, 58-139513, 8-97674, and 7-335995.
A conventional method for manufacturing substrates in which a mother substrate is provided with electrode patterns and the mother substrate is cut into a plurality of individual substrate elements has been widely used. In the conventional method, a mother substrate 1 shown in FIG. 22 is used. The mother substrate 1 shown in FIG. 22 is provided with through-holes 4 at positions corresponding to the four corners and to a portion of each lateral side of a substrate element to be formed. Each through-hole 4 is provided with an electrode 2 on the inner surface thereof (see FIG. 23). The mother substrate 1 is cut along cut lines D by a dicer or similar cutting apparatuses into substrate elements, such as a substrate element 3 shown in FIG. 23.
However, in the conventional method, a problem exists in that a plurality of molds, for forming the mother substrates 1, are required to be provided with pins according to the number of through-holes 4 of the substrate elements 3, thereby increasing the cost of the molds, and consequently increasing the manufacturing costs of the substrate elements 3. Moreover, in the method in which the mother substrate 1 is provided with a plurality of the through-holes 4 at the lateral surfaces of the substrate elements 3, short circuits between the electrodes 2 and cracking of substrates are likely to occur when the through-holes 4 are excessively close to each other, whereby miniaturization of the substrate elements 3 is prevented.
In order to overcome the problems described above, preferred embodiments of the present invention provide an apparatus and method for efficiently manufacturing mother substrates and miniaturized substrate elements.
In a preferred embodiment of the present invention, a mother substrate for forming a plurality of substrate elements having electrodes on the lateral side surfaces and the longitudinal end surfaces thereof includes a region in which the plurality of substrate elements are provided, the region including at least one elongated through-hole. The elongated through-hole is located in the region such that an entire longitudinal end surface of a first substrate element and a portion of a lateral side surface of a second substrate element are exposed.
In the mother substrate, the elongated through-hole may be located at the inner surface of a longitudinal end that is flush with a lateral side surface of the second substrate element. The inner surface of a longitudinal end of the through-hole may also be provided with the side surface electrode.
According to another preferred embodiment of the present invention, a substrate element having electrodes on a lateral surface thereof and a longitudinal end surface thereof, is manufactured by a method including the steps of providing a mother substrate, forming at least one elongated through-hole such that an entire longitudinal end surface of the first substrate element and a portion of a lateral surface of the second substrate element are exposed, forming an electrode pattern on the inner surface of the at least one elongated through-hole, and cutting the mother substrate along lines extending in the vicinity of the longitudinal ends of the at least one elongated through-hole and in a direction that is substantially perpendicular to the longitudinal axis of the elongated through-hole.
According to another preferred embodiment of the present invention, an electronic device includes a substrate element having electrodes on a lateral surface thereof and a longitudinal end surface thereof, manufactured by a method including the steps of providing a mother substrate, forming at least one elongated through-hole on the mother substrate such that an entire longitudinal end surface of a first substrate element and a part of a lateral surface of a second substrate element are exposed, the first and the second substrate elements being adjacent to each other and having a common lateral surface thereof, forming an electrode on an inner surface of the at least one elongated through-hole to define an end surface electrode of the first substrate element and a side surface electrode of the second substrate element, cutting the mother substrate along lines extending in a vicinity of the longitudinal ends of the at least one elongated through-hole and in a direction that is substantially perpendicular to the longitudinal axis of the at least one elongated through-hole, and an electronic device element mounted on the substrate element.
In preferred embodiments of the present invention, an elongated through-hole is preferably provided in a mother substrate so that an entire longitudinal end surface of a first substrate element and a portion of a lateral surface of a second substrate element are simultaneously exposed, in which the first and the second substrate elements are adjacent to each other and have a common lateral surface thereof. By forming an electrode on the inner surface of the elongated through-hole, an end surface electrode of the first substrate element and a side surface electrode of the second substrate element are easily formed simultaneously. With this arrangement, the number of through-holes can be reduced compared to a conventional method, thereby reducing the manufacturing cost of substrates. Moreover, by reducing the number of through-holes compared to a known mother substrate, problems such as the strength of the substrate being decreased by adjacent through-holes being excessively close to each other is prevented. Therefore substrate elements according to preferred embodiments of the present invention are greatly miniaturized.
Other features, elements and advantages of the present invention will be described in detail below with reference to preferred embodiments of the present invention and the attached drawings.